An update is available for Windows Defender on Windows Vista

There is a code defect in the functionality of Windows Defender malware sample submission. This defect prevents Microsoft from receiving requested samples from Windows Defender users.

An update to Windows Defender has been released as an optional software update on Windows Update. This update corrects the code defect so that Microsoft can receive requested samples. Administrators can manually download and install the update to Windows Defender.

The following files are available for download from the Microsoft Download Center:

Download the Update for Windows Vista (931099) package now.

Download the for Windows Vista for x64-based Systems (931099) package now.

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.


Customers can choose to participate in Microsoft SpyNet. Customers can choose to participate in Microsoft Spynet by selecting an option in the Windows Defender options. Windows Defender automatically submits Microsoft Spynet report data to Microsoft. Microsoft reviews this customer data. When additional analysis is needed, Microsoft may send a request for a software sample. This request appears in a Windows Defender dialog box. If the user consents, the sample is uploaded to Microsoft. Microsoft then analyzes the collected samples for potential risk. This analysis helps protect customers from malicious and potentially unwanted software.

To manually install this update, you must be logged on with administrator permissions.